Mechanical Evaluation of Articulated Instruments and Cross-handed Manipulation in Laparo-endoscopic

Jiangfan Zhu, MD

East Hospital, Tongji University School of Medicine

Background:Laparo-endoscopic single-site surgery ( LESS ) is limited by loss of triangulation and internal instruments conflict. To overcome these obstacles, some approaches have been introduced: articulated instruments and cross-handed manipulation which causes the right hand to control the left instrument tip and vice versa. The aim of this study was to compare task performance of these approaches based on a mechanical evaluation platform.

Methods:A LESS mechanical evaluation platform was set up to investigate the performance of two tasks (suture pass-through rings and clip-cut) in the three groups: uncrossed manipulation with straight instruments (Group A, the control group), uncrossed manipulation with articulated instruments (Group B), and cross-handed manipulation with articulated instruments (Group C). The operation time and workload when completing the standard tasks were measured.

Results:Group A presented significantly better time scores than group B, and group C was more time consuming in comparison to group A and group B during the performance of the tasks(P<0.05). Comparing of average load required to perform the suture pass-through rings task, it differed significantly betweendominant and nondominant hand in all groups(P<0.01) and was less in group A and group B than group C in dominant hand (P<0.01) ,while almost the same in all groups in the nondominant hand. In terms of average loadrequirement to accomplish clip-cut task, it was almost equal not only betweengroup A and B, but also between dominant and nondominant hand while theincrease reached statistical significance comparing group C with other groups(P<0.05).

Conclusions:Compared with conventional devices and maneuvering techniques, articulatedinstruments and cross-handed manipulation are associated with longeroperation time and higher average load. More comfortable, effective andfavorable instruments should be developed in the future for laparo-endoscopicsingle-site surgery.